1. Field of the Invention
The present invention relates to a semiconductor device.
2. Description of the Related Art
FIG. 9 is a plan view showing a semiconductor device of a related art (for example, see JP 2005-310807 A). In a semiconductor device 100, rectangular dummy conductor patterns 102 are formed near a wiring 101. The dummy conductor patterns 102 are provided so that the wiring 101 can be easily processed at the time of production of the semiconductor device 100. In addition, the wiring 101 functions as an inductor.
Note that, related art documents relevant to the present invention include JP 2005-285970 A and Ali Hajimiri et al., “Design Issues in CMOS Differential LC Oscillators”, IEEE JOURNAL OF SOLID-STATE CIRCUITS, V01. 34, No. 5, May 1999, pp. 717-724, in addition to JP 2005-310807 A.
The present inventor has recognized as follows. In a case where a high-frequency current flows through the wiring 101 in the semiconductor device 100 shown in FIG. 9, the following problem arises. That is, as shown in FIG. 10, by a magnetic field generated by the wiring 101, an eddy current is generated in each of the dummy conductor patterns 102 positioned near the wiring 101. FIG. 10 is a plan view of an enlarged portion surrounded by the dotted line of FIG. 9. A direction of the current flowing through the wiring 101 is indicated by an arrow A1 of FIG. 10, and a direction of the eddy current flowing in the dummy conductor pattern 102 is indicated by an arrow A2 of FIG. 10.
When the eddy current is generated as described above, according to Lentz's law, a magnetic field in a direction in which the magnetic field generated by the wiring 101 is offset is generated. Accordingly, a circuit constant of the wiring 101 fluctuates, which results in instability of transmission characteristics of the wiring 101. The problem becomes prominent when the high-frequency current with a frequency of 5 GHz or higher flows through the wiring 101.